mitsuguy

iTrader: (2)

thats pretty much inaccurate, unless we are talking about low silicon content forged pistons... my car, as well as many/most others that you see at the nightly drags have stockish internal motors which rarely ever means forged...

we are talking less than thousandths of an inch here though...

Arcadian

Here's my experience.
I live where it gets cold. I always warm my cars anywhere from a couple of minutes to as long as 7-10 minutes (when its -30C). In summer, I warm the engine about 1 minute in the morning. I've only owned 5 cars in 30 years because I usually get 300-400,000KM out of them. Never had an engine apart, ever.

BDSL

For cold winter, you should use a block heater for cold temperature.

Whether it is summer or winter, there is no need to idle the car for more than 10-20 seconds. Operating oil pressure is reached within the first few seconds once the engine is running. Excessive idling is just wasting gas.

BDSL

http://www.annapolisroyal.com/visitor-idle.php

http://www.dadacanada.com/index.php?...id=1&Itemid=32

Globalinx

I warm mine every time. Aside from getting oil pressure up, it helps to get the engine components to get warmed up. Metal when cold, is brittle. Also, when cold, some components may not all be expended to their operating dimensions. This will cause additional friction - ware. So, warm up, and don't drive the car hard till the operating temperature is reached. The GreenPiece wants you to start driving immediately after you start the car because they want you to warm up the engine fast, as cold starts produce more pollutants than a hot motor. The government and car manufactures are backing up the dumb idea, as every new car sold, brings money in to their pockets. So, don’t be waiting on them to come out and suggest warming the car up before the drive. Now, most modern cars are fitted with cast internals due to emissions regulation, which are more prone to be damaged by detonation as they are more brittle, but better for the environment during the initial start.

BDSL

Just read your owner's manual. It will tell you exactly what to do on cold weather startup.

oscar430

You still should give a little time for the combustion chambers to expand a little bit on cold days, perhaps 30-45 seconds would help prevent cold piston scoring & give the O2 sensors a bit of a warm up.

BDSL

There is a reason why Toyota/Lexus engineers specified the cold startup precedures in the owner's manuals.

Unless it is proven through controlled experiements, I don't know why some people like to invent new ways to do things.

By the way, when engine is "cold", it runs in open loop. Therefore O2 sensor reading is not used by the ECU. O2 sensor reading is used by the ECU (i.e. closed loop) when the engine water temperature reaches operating temperature (i.e. +150degF). That 30-45 seconds will NOT bring the engine water temperature to +150degF.

gemigniani

But nowadays owners manuals have hidden environmental agendas; e.g. the 0W-20 oil viscosity recommendation for newer Lexus's is strictly for maximum fuel economy, but 0W-20 not the best choice for maximum engine longevity in warm weather. Ditto the owners manuals recommendation to never change the transmission fluid - sure that's great for greenie reasons, but owners never change the fluid won't ever become members of the Toyota 300,000 mile club.

In the days before major emission controls (i.e. pre-1975 days) Toyota and Datsun owners manuals recommended idling the engine for a few minutes on cold days before driving. Then as soon as they added catalytic converters, they recommended driving right away to get the converter warmed up quicker to minimize tailpipe emissions.

BDSL

Are you sure about that? Owner's manual recommends NEVER to change the transmission fluid??


Thats because they were using carburetors which became obsoleted around 1980s. Electronic fuel injection replaced carburetor. It has nothing to do with catalytic converters.

http://en.wikipedia.org/wiki/Fuel_injection
"Operational benefits to the driver of a fuel-injected car include smoother and more dependable engine response during quick throttle transitions, easier and more dependable engine starting, better operation at extremely high or low ambient temperatures, increased maintenance intervals, and increased fuel efficiency. On a more basic level, fuel injection does away with the choke which on carburetor-equipped vehicles must be operated when starting the engine from cold and then adjusted as the engine warms up."

gemigniani

OK, to settle this debate once and for all I will quote from the 1983 Celica owners manual (in 1983 the Celica came with both a carbureted 22R engine and an optional 22R-E fuel injected engine).

For the carbureted 22R engine the 1983 Celica owners manual says:

"If the weather is below freezing fully depress and release the accelerator pedal three or four times then crank the engine with your foot off the accelerator pedal. After the engine runs for about 30 seconds, tap the accelerator pedal once to reduce the idle speed. Let the engine warm up for a few minutes before driving."

For the fuel injected 22R-E engine the 1983 Celica owners manual says:

"With your foot off the accelerator pedal, crank the engine by turning the key to Start. After the engine warms up for about 10 seconds you are ready to drive. If the weather is below freezing let it warm up for a few minutes before driving."

blackrx330

If it was lease vehicle or rental car, I couldn't care less about letting it warm up. Just start and go...even in -30 F! Blast the heater to full in the winter and A/C to full in the summer. Who cares about oil pressure and all. But if it was my own personal car that I would want to keep it running for a long time, I always warm up it a good 2-3 minutes in freezing weather and 20-30 seconds in the summer before I go. Letting the engine warm up makes it operate smoother, give less hesitation, and defrost the windows faster. I don't really care about wasting gas or emission crap; I care more about my car's longevity and comfort! and letting it idle for a few minutes have not done any harm in any way for the past 30 years I've been driving.

GSteg

iTrader: (15)

About 45 seconds for me at 50F temperature. If it's lower than that, I usually give it an extra 15 seconds.

sethjon

Depends on how cold it is outside. It takes time for the oil to warm up so that it can easily slide in and out lubing the parts. If you don't warm it up a little over time you will get more wear.

BentValve

+ 1. When its in the teens, I will let it run for a minute or so.